Design and Functional Characterization of a Novel Abscisic Acid Analog

• Published in: Scientific reports 2017-03, Vol.7 (1), p.43863, Article 43863
• Main Authors: Han, Xiaoqiang, Jiang, Lun, Che, Chuanliang, Wan, Chuan, Lu, Huizhe, Xiao, Yumei, Xu, Yanjun, Chen, Zhongzhou, Qin, Zhaohai
• Format: Article
• Language: English
• Subjects: 631/154/309; 631/92/2783; Abscisic acid; Abscisic Acid - chemical synthesis; Abscisic Acid - chemistry; Abscisic Acid - pharmacology; Aquatic plants; Arabidopsis - growth & development; Arabidopsis Proteins - agonists; Arabidopsis Proteins - chemistry; Arabidopsis Proteins - metabolism; Crystal structure; Crystallography, X-Ray; Drug Design; Elongation; Germination - drug effects; Humanities and Social Sciences; Hydrogen bonding; Hydrophobicity; Inactivation; Lactuca - growth & development; Models, Chemical; Molecular Structure; multidisciplinary; Oryza - growth & development; Oxidation; Plant growth; Plant Growth Regulators - chemical synthesis; Plant Growth Regulators - chemistry; Plant Growth Regulators - pharmacology; Plant hormones; Protein Phosphatase 2C - antagonists & inhibitors; Protein Phosphatase 2C - metabolism; Receptor mechanisms; Receptors, Cell Surface - agonists; Receptors, Cell Surface - chemistry; Receptors, Cell Surface - metabolism; Science; Seed germination; Seedlings; Seedlings - drug effects; Seedlings - growth & development; Seeds - drug effects; Seeds - growth & development
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/srep43863

The phytohormone abscisic acid (ABA) plays a crucial role in mediating plant growth and development by recruiting genetically redundant ABA receptors. To overcome its oxidation inactivation, we developed a novel ABA analog named 2′,3′-benzo- iso -ABA ( iso -PhABA) and studied its function and structural characterization with A. thaliana ABA receptors. The (+)- iso -PhABA form showed much higher ABA-like activities than (+)-ABA including inhibitory effects on the seed germination of lettuce and A. thaliana , wheat embryo germination and rice seedling elongation. The PP2C (protein phosphatases 2C) activity assay showed that (+)- iso -PhABA acted as a potent and selective ABA receptor agonist, which is preferred to PYL10. In some cases, (−)- iso -PhABA showed moderate to high activity for the PYL protein inhibiting PP2C activity, suggesting different mechanisms of action of iso -PhABA and ABA. The complex crystal structure of iso -PhABA with PYL10 was determined and elucidated successfully, revealing that (+)- iso -PhABA was better coordinated in the same binding pocket compared to (+)-ABA. Moreover, the detailed interaction network of iso -PhABA/PYL10 was disclosed and involves hydrogen bonds and multiple hydrophobic interactions that provide a robust framework for the design of novel ABA receptor agonists/antagonists.